Milton



(No Model.)

M. o. REEVES. l SPEED VAE-EINE MEGHANISM.

No. 583,402. Patented May 25,'*1891 jagd,

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UNTTED STATES PATENT EEICE.

MILTON O. REEVES, OF COLUMBUS, INDIANA, ASSIGNOR TO THE REEVES PULLEYCOMPANY, OF SAME PLACE.

SPEED-VARYING NIECHANISIVI.

SPECIFICATION forming part of Letters Patent No. 583,402, dated May 25,1897. Application led October l2, 1896. Serial No. 608,552. (No model.)

T0 @ZZ whom t may concern,.-

Be it known that I, MILTON O. REEVES, a citizen of the United States ofAmerica, residing at Columbus, in the county of Bartholomew and State ofIndiana, have invented certain new and useful Improvements inSpeed-Varying Mechanism, of which the following is a specification.

The ordinary cone of pulleys is the most common speed-varying mechanismin use, but its defects are well recognized. Among the many attempts tobetter the art devices have been constructed consisting of pairs oftruncated cone-shaped disks, each pair feathered to a shaft with theirsmall ends facing each other, so as to present a deep V-shaped groovebetween them. The corresponding members of each pair were so connectedthat as the members of one pair were moved away from each other themembers of the other pair were moved toward each other. A bevel-edgeddriving-belt was stretched between the pairs of disks, and as the disksof one pair were moved apart the belt moved nearer the shaft, thusworking on a smaller driving diameter, and the disks of the other pairmoved toward each other and the belt assumed a position within thelatter pair at a greater driving diameter, thereby varying the speed ofone shaft relatively to the other. The theoretical advantages in thisarrangement are recognized, but certain practical defect-s haveprevented its use. It was found that when the belt was tighthbetween alarge driving diameter and a small diameter it would be loose whenworkin g at diameters between the large and small one. This is due tothe fact that the belt in working from a large to a small diametercontacts with more than half of the large pulley and relatively less ofthe small, while the belt Working on equal diameters passes around halfof each. Comparing two pulleys one larger than the other with twopulleys each of a diameter equal to the mean diameter of the other two,the two of unequal size will require a belt longerby about one-half ofthe excess of belt contact on the large pnlley above one hundred andeighty degrees minus one-half of the deficit of belt contact on thesmaller pulley under one hundred and eighty degrees, and the excessincreases as the distance between the pairs of pulleys decreases, andvice versa.

The object of my invention is to overcome this defect and maintain auniform tension on the belt.; and the invention consists in substitutingfor the cone-disks disks of the cone order having their driving-facesbulged or convened in such manner as to automatically take up or let outslack as the driving diameters of the disks recede from or approach themean diameter.

In the drawings, Figure 1 is a plan, and Fig. 2 a side elevation. Fig. 8is an end section of the belt.

Mounted inaframe l are two parallel shafts 2, one being the driving` andthe other the driven shaft. 3 and 4 are pairs of disks in the form ofoblate spheroids and are feathered, respectively, to one ofthe shafts 2with their smaller bases facing each other, so as to present a deepcurved V-shaped groove between the pairs. Each disk is provided with ahub 5, adapted to contact with sleeves or collars 6, movably mounted onthe shafts. The collars contacting with one member of each pair of disksare connected by a lever 7, pivoted half-way between the shafts at S andhaving an end 9, carrying a threaded collar 10. The collars contactingwith the other member of each pair are connected by a lever 1l, similarto lever 7 and similarly pivoted and provided with an end 13, carrying athreaded collar 14. Passing through the threaded collars 10 and lt is ascrew-shaft l5, having a right-hand-threaded portion and aleft-handthreaded portion, each adapted to cooperate with one of thethreaded collars and move them simultaneously when the shaft is rotatedeither toward or away from a common point. The outer end of screw-shaftl5 is provided with a sprocket-wheel 16, adapted to be rotated by asuitable chain. Vhen the screw-shaft is rotated, the members of one pairof disks'are moved apart,while the members of the other pair are movedtoward each other. Stretched between the pairs of disks is a belt 17,preferably provided with beveled driving edges adapted to contact withthe driving-faces of the disks. The belt preferably consists of acontinuons strip 18, having lateral strips 19 secured to one side andlat- ICO eral strips 2O secured to the other side, thus making a beltrigid in cross-section and ilexi ble longitudinally. As the disks of onepair move apart the belt moves nearer the shaft, thus reducing thedriving diameter of the pulley, and simultaneously the other pair ofdisks move toward each other, and the belt moves on the disks to agreater driving di ameter, thus varying the speed of one shaftrelatively to the other. The curvature of the disks automaticallycompensates for the different lengths of belt required, and the belt iskept at a uniform tension.

I claimw 1. The combination, in a speed-varying mechanism, of a shaft, apair of driving elements movably mounted thereon having oblate spheroiddriving-faces; aV seeond shaft; a pairof driving elements of likeconstruction thereon, a belt connecting the pairs of driving elementsand having driving edges eonforming to the oblate spheroid driving-faees, and means for simultaneously moving the members of one pair ofdriving elements toward each other, and the members of the other pairsaway from eaeh other, substantially as and for the purpose set forth.

2. rlhe Combination, in a speed-varying mechanism, of a shaft, a pair ofdrivingelements movably mounted thereon having 0blate spheroiddriving-faces, a second shaft,

a pair of driving elements of like constructionthereon, a beltconnecting the pairs of driving elements, and having driving edgesoonforining to the oblate spheroid driving-faces,

levers connecting the CorrespondingmembersY MILTON O. REEVES.

'itnesses:

H. L. PEARsoN, JNO. JEWELL.

